On an older machine, grinding can be normal
Whirlpool dishwashers come in two designs, and which one you have changes what a noise means. Older machines chop food waste as part of the wash, so a grinding sound during the cycle is the machine working. Newer machines have a removable filter instead, and a grind there means something hard has reached the sump. Look at the tub floor first: a filter that twists out by hand tells you which page of this list applies to you.
What you are seeing
- A grinding sound during the wash portion of the cycle.
- A hard rattle or crunch rather than a steady grind.
- A rhythmic tap while the machine runs.
- A knock in the pipework as the machine fills.
- Not this fault: A short hum during the drain is normal.
- Not this fault: Water rushing at the start of a fill is normal.
Most likely causes, in Whirlpool order
- Normal grinder operation on an older machine — Why ranked: First because it is not a fault, and mistaking it for one accounts for a real share of calls on this platform.
- Something hard in the filter or the sump — Why ranked: Second because on a filter machine it produces the same sound and does need clearing, and leaving it damages the pump.
- Spray arm striking an item in the rack — Why ranked: Ranked here because a rhythmic tap has no other explanation and is corrected by reloading.
- Water hammer in the supply line — Why ranked: It arrives only at fill, which separates it from everything that happens during the wash.
- Wash motor or its bearing worn — Why ranked: Last. It is the most expensive answer and it presents as a constant noise rather than an intermittent one.
What to check, in order
- Look at the tub floor for a filter that twists out by hand. — Because: It decides whether rank one applies at all, and the two designs need different answers.
- Note exactly when in the cycle the noise happens. — Because: Timing separates the remaining causes faster than the sound itself.
- On a filter machine, twist the filter out and feel round the sump. — Because: Rank two is the commonest genuine finding and needs no tools.
- Spin each spray arm by hand and check nothing in the racks blocks it. — Because: Rank three is confirmed the moment an arm catches on something.
Checks you can do safely
- Open the door and look at the tub floor: note whether there is a filter that twists out by hand. — N: 1 — Tools: Torch — Time: quick
- Run a cycle and write down exactly when the noise occurs - fill, wash, or drain. — N: 2 — Tools: Notepad — Time: one cycle
- On a filter machine, twist the filter out, rinse it and feel carefully round the sump for glass or hard debris. — N: 3 — Tools: Gloves, torch — Time: moderate
- Spin each spray arm through a full turn by hand and move anything that catches it. — N: 4 — Tools: None — Time: quick
- Stop rule: Stop here. Removing the pump cover, a grinder assembly or the motor is service work.
Before you reach into the tub
Safety
Switch off the dishwasher breaker before reaching into the sump. A capacitor can hold a charge after the power is off. The water in a tub can still be hot at the end of a cycle. Broken glass in the sump is common; use gloves and a torch, not bare fingers. Never reach towards a grinder area with the machine powered.
When this becomes a service call
A grind or rattle continues with the filter and sump confirmed clear. The noise is constant at every stage of the cycle. A grinding machine has become noticeably louder than it used to be. Any burning smell during a cycle - kill the breaker and stop.
Nearest pages
What this page does not cover
This is generalized information for Whirlpool dishwashers as a group, ranked from the sound. It does not say which models grind and which filter, or name parts. If the noise began after a specific event, start from the history page below.
Links down: - [Whirlpool Dishwasher: Abnormal Noise or Vibration](/blog/whirlpool-dishwasher-abnormal-noise-2)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
